The present invention relates generally to a multiple pin heatsink device and method. In the electronics industry, it has been well known to employ multiple pin heatsinks to dissipate the heat generated by electronic components on a printed circuit board. These known heatsinks typically include a base plate which is directly mounted to the circuit board with a number of pins attached thereto extending from the upper surface for maximum exposure to the surrounding air. For effective heat dissipation, the base plate and the pins are composed of a heat-dissipating metal alloy.
In general, these pin fin surfaces suffer from high production costs as compared to other devices in the competitive heat transfer field. While the pin fin-type heatsinks have high performance capabilities, their actual commercial uses have been restricted due to the high production costs. Such high costs to manufacturers of such pin fin heatsinks result from high material outlay to cut the pin patterns from solid or extruded shapes as well as the fixturing and brazing costs associated with attaching the pins to the base plate surfaces.
It has been known in the prior art to employ U-shaped pin pairs of wire elements for constructing a heatsink device. Such U-shaped wire elements have advantages over individual pins in the assembly of heatsinks in that the connecting central portion of the U-shaped wire element provides a wide surface area for securing the wire element to the base plate which includes an increased surface area for maximum heat dissipation. However, these U-shaped wire elements must be affixed to a base plate surface by a laborious and costly metallurgical process such as brazing, welding, or soldering. For example, the U-shaped wire elements are introduced into a die made of paper for maintaining the wire elements in the desired array with central portions, which connect the two pins together, exposed above the die. Solder paste is then applied to the central portions and then a substrate is placed in contact with the central portions with solder paste thereon. The entire fixture is heated in an oven to cure the solder paste and burn off the paper die to leave a base element with upstanding pins connected thereto. This is a time consuming, tedious and relatively expensive procedure. Solder paste or brazing compound must be purchased and properly applied; the pins must be held in place and heat must be properly applied. Similarly, welding techniques are likewise expensive, time consuming and complex and often provide less than optimum results.
As an alternative to employing U-shaped wire elements, the pin fin arrangement may be cast. However, casting methods require expensive molds and heat sources. Further, the metal alloys employed in the casting of multiple pin heatsinks are typically limited to materials which are relatively poor conductors of heat. Also, the casting process itself reduces the heat dissipation of the metal alloys because porosity and granular structure are typically formed in the cast pins. Moreover, due to the surface tension of the molten pin material, it is extremely difficult to draw that material into the extremely narrow pin molds even using a vacuum pump.
In view of the foregoing, a multiple pin heatsink device, which can be easily manufactured at low cost without brazing, soldering or welding is desired. In particular, there is a need for a multiple pin heatsink device which can be formed and assembled mechanically while still employing the preferable U-shaped wire elements for forming the pins of the heatsink device.